Phosphating compositions



2,809,906 Patented Oct. 15, 1957 PHOSPHATING COMPOSITIONS Henry J. Baecker, Wyandotte, Edward J. Kubis, Allen Park, and Andrew W. Liger, Wyandotte, Mich., assignors to Wyandotte Chemicals Corporation, Wynndotte, Mich, a corporation of Michigan No Drawing. Application November 25, 1952, Serial No. 322,584

6 Claims. (Cl. 148-6.15)

The present invention relates to phosphating-cleaner compositions which are characterized by having low foaming properties. Specifically, the invention relates to phosphating-cleaner compositions which contain as the principal organic detergent a conjugated polyoxypropylene-polyoxyethylene detergent of the type disclosed in U. S. Patent No. 2,674,619, granted April 6, 1954, to Lester G. Lundsted.

It is well known in the metal finishing art that steel will react with phosphoric acid or the acid salts thereof to produce a phosphate coating on the steel. This so-called phosphating process is widely used since the coating produced thereby prevents rusting of the metal and provides an excellent base for paint. To successfully phosphate steel, however, it is essential that its surface be clean. Many phosphating compositions are designed for use only with steel that is cleaned immediately before the phosphating step and these phosphating compositions generally consist of orthophosphoric acid solutions, which may also contain minor proportions of certain salts to accelerate the formation of the coating as well as to modify the nature of the coating. A second class of phosphating compositions that is widely used in the art is designed for use with steel that is not specially cleaned before the phosphating step and these compositions are known as phosphating-cleaners since they simultaneously clean the steel and deposit a phosphate coating thereon. Phosphating-cleaners differ from simple phosphating com positions in that they contain a substantial portion of an organic detergent which removes soil from the steel and thereby insures a good phosphate coating.

There are two general methods of phosphating which are used in industry. The first is the so-called tank method in which the steel part that is to be phosphated is simply soaked in an unagitated tank of aqueous phosphating composition. The second and more popular method is to apply the phosphating composition to the steel by means of spray washing equipment. The major advantage of the spray method is that the steel parts can be phosphated in much shorter processing cycles.

A major shortcoming of many phosphating-cleaner compositions is that they foam excessively when applied in spray washing equipment. The foaming problem is quite complex and is partially a function of the design of the spray equipment, but essentially it is a problem that is inherent in the use of organic detergents. Many attempts have been made to ameliorate this foaming problem, but such attempts have been at most only partially successful. An obvious method of reducing foaming is to lower the concentration of organic detergent, but this is not practical since it results in poorer or slower cleaning and, consequently, a poorer phosphate coating. It has been recognized in the art that nonionic detergents as a class foam less than the anionic types and as a result this class of detergents has found wide use in p osphating-cleancr compositions. Although the use of nonionic detergents has reduced the foaming tendencies of such compositions, the difference is one of degree rather than kind and the use of these compounds has not eliected the substantial reduction in foaming that the art is seeking.

It is an object of this invention to provide improved phosphating-cleaner compositions having extremely low foaming properties.

Other objects and advantages of this invention will become apparent from the following detailed description thereof.

We have now discovered certain novel phosphatingcleaner compositions which are characterized by excellent low foaming properties and which contain as the principal organic detergent a conjugated polyoxypropylene-polyoxyethylene compounds having the following formula:

Y is the residue of an organic compound containing therein x hydrogen atoms capable of reacting with 1,2 propylene oxide x is an integer greater than one y has a value such that the molecular weight of the compound, exclusive of the oxyethylene groups, is at least 900, and

it has a value such that the oxyethylene groups constitute about 10-90% of the total weight of the compound.

The properties and the preparation of these conjugated polyoxypropylenc polyoxyethylene compounds are set forth in U. S. Patent No. 2,674,619, granted April 6. 1954, to Lester G. Lundsted which description is in corporated herein by reference.

in addition to the organic detergent, balanced phosphating-cleaner compositions may contain as an essential or optional ingredient, an alkali phosphate salt such as monosodium, monoammonium or monopotassium orthophosphate, or mixtures thereof, activators such as sodium molybdate, sodium nitrate, and sodium chromate. organic acids to adjust the pH and solvents, etc. It is customary for the phosphate salt to constitute about of the formulation, and to include in the formulation approximately 1% of the above noted activators, although this is not absolutely essential. Organic acids such as oxalic acid, glycollic acid, etc., may be included in sufficicnt quantity to adjust the pH of the phosphating solution to the value desired, which is usually in the range of 3.0-6.5. The proper formulation of the above ingredients to obtain a satisfactory balanced composi tion is well within the skill of the art and does not constitute a part of the present invention. The present invention resides in the discovery that the incorporation of the conjugated polyoxypropylene-polyoxyethylene compound as the principal organic detergent greatly reduces the foaming properties of the phosphating-cleaner composition and, consequently, materially broadens the utility thereof.

Phosphatingcleaner compositions usually contain approximately 2S% organic detergent, although smaller or larger quantities may be used where indicated by the condition and type of steel to be phosphated. The term principal organic detergent means that the detergent (in this case is a conjugated polyoxypropylene-polyoxyethylene compound) constitutes at least 50% of the total detergent content included in the phosphatingcleaner composition and preferably contains a substantially larger proportion. Although the conjugated polyoxypropylene-polyoxyethylene compound can be the sole detergent contained in the composition, other known cationic, nonionic or anionic detergents, or combinations thereof, may be employed in amounts almost equal to the polyoxy compound, although much smaller amounts 3 are preferred. When. confronted. with. a. difi'icult. cleaning condition, it is sometimes advantageous to include such secondary detergents in the composition, since it is well known in the artthat: many types of soil are. preferentially cleaned by different types of detergents. It must be recognized, however, that these secondary detergents usually substantially increase the foaming properties, and a preferred embodiment of this invention is a phosphatingcleaner composition containing as the sole detergent compound, a conjugated polyoxypropylene-polyoxyethylene compound of the type described.

The foaming. characteristics of the phosphating-cleaner compositions are measured by the foam height test procedure set. forth below:

FOAM HEIGHT TEST PROCEDURE A phosphating-cleaner composition is prepared in a 2 ounce/gallon aqueous solution. The solution is then heated to the test temperature and 200 ml. of the solu tion is poured into a 250 ml. glass stoppered graduate. The solution in the graduate is then shaken vigorously twenty-five times and as soon as a definite line of demarcation appears between the solution and the foam, the height of the foam is measured from this line in inches. The glass stopper is not removed from the graduate at any time.

The following examples are set forth to more clearly illustrate the principle and practice of this invention to those skilled in the art:

Example 1 The following phosphating-cleaner composition was prepared:

Component: Weight percent Monosodium orthophosphate 91.5 Sodium molybdate 1.0 Pine oil 3.0 Glycollic acid, 70% 1.0 Sodium dibutylnaphthalene sulfonate 0.5 Alkylaryl polyethoxyether 1 3.0

1 Condensation product nonylphenol and ethylene oxide.

It is seen that the composition contains 3.5% wetting agent, principally of the nonionic type. The foaming characteristics of the composition were determined at 135 F. and 165 F. and the following results were obtained:

TABLE 1 Temperature, F.: Foam height, inches 135 4 O 165 3 3 Experience has shown that the above composition foams excessively in certain types of commercial spray washing equipment, and as a result, it may be concluded that a satisfactory phosphating-cleaner composition must have a foam height of less than 3 inches to be considered satisfactory.

Example 2 The following phosphating-cleaner composition was prepared:

Component: Weight percent Monosodium orthophosphate 91.5 Sodium molybdatc 1.0 Pine oil 3.0 Glycollic acid, 70% 1.0 Sodium dibutylnaphthalene sulfonate 0.5 Alkylaryl polyethoxyether 1 1.0 Conjugated polyoxypropylene-polyoxyethylene compound 2.0

1 Condensation product nonylphenol and ethylene oxide.

The polyoxypropylene-polyoxyethylene compound was prepared by condensing propylene oxide with propylene glycol to prepare a polyoxypropylene glycol of 1800 moleeular weight, and ethylene oxide was then condensed therewith. until the oxyeth-ylene groups constituted 15% of the resultant product. It is seen that the above composition is identical with the one of Example 1 except that 2% of the alkylaryl polyethoxyether was replaced with the conjugated polyoxypropylene-polyoxyethylene compound. The foam heights of the composition at 135 F. and 165 F. areset. forth below:

TABLE II Temperature, F.: Foam height, inches 135 0.8 165 0.5

Comparing the above results with Table I, it is seen that the conjugated polyoxypropylene-polyoxyethylene compound reduced the foaming by at least Example 3 The following phosphating-cleaner composition was prepared:

Component: Weight percent Monosodium orthophosphate 92.0 Sodium. molybdate 1.0 Pine oil 3.0 Glycollic acid, 70% 1.0 Alkylaryl polyethoxyether 1 1.0 Conjugated p0lyoxypropylenc-polyoxyethylene compound 2 2.0

Condensation product nonylphenol and ethylene oxide.

1 Product described in Example 2.

It is seen that this product is identical with the composition of Example 2 except that the 0.5% sodium dibutylnaphthalene sulfonate was removed. The following foam heights were obtained at F. and F.:

TABLE In Temperature, F.: Foam height, inches 135 0.1 165 0.1

Comparing the data of Table III with those of Table II, it is seen that the deletion of the sodium dibutylnaphthalene sulfonate results in a further substantial reduction in foam height.

Example 4 TABLE IV.ST'RUCTUHE POLYOXYPROPYLENE- POLYOXYETHYLENE COMPOUND Weight Foam Molecular Weight, Polyoxypropylenc Portion Percent; Height,

Oxyethyl- Inches one at 165 F.

1,800 9 1 0.8 1,300 ll 0. 8 1,800 l5 0. 5 1,800 26 0. 5 1,800 32 0.3

It is seen from the above data, that the weight percent oxyethylene groups in the conjugated polyoxypropylenepoloxyethylene compound is not critical and any compound conforming to the generic formula previously set forth is operable in the present invention.

What is claimed is:

1. In phosphating-cleaner compositions consisting essentially of phosphate salt and organic detergent, the improvement wherein at least 50% by weight of said detergent consists of a conjugated polyoxypropylenepolyoxyethylene compound having the formula wherein Y is the residue of an organic compound containing therein x hydrogen atoms capable of reacting with 1,2-propylene oxide, x is an integer greater than one, y has a value such that the molecular weight of the compound, exclusive of the oxyethylene groups, is at least 900, and z has a value such that the oxyethylene groups constitute about -90% of the total weight of the compound.

2. In phosphating-cleaner compositions consisting essentially of phosphate salt and organic detergent, the improvement wherein said organic detergent consists of a conjugated polyoxypropylene-polyoxyethylene compound having the formula wherein Y is the residue of an organic compound containing therein x hydrogen atoms capable of reacting with 1,2-propy1ene oxide, 2: is an integer greater than one, y has a value such that the molecular weight of the compound, exclusive of the oxyethylene groups, is at least 900, and 2 has a value such that the oxyethylene groups constitute about 10-90% of the total weight of the compound.

3. A phosphating-cleaner composition consisting essentially of phosphate salt and organic detergent, said salt comprising about 90% by weight of said composition and said detergent comprising about 28% by weight of said composition and at least 50% by weight of said detergent consisting of a conjugated polyoxypropylene-polyoxyethylene compound having the formula wherein Y is the residue of an organic compound containing therein 1: hydrogen atoms capable of reacting with 1,2-propy1ene oxide, x is an integer greater than one, y has a value such that the molecular weight of the compound, exclusive of the oxyethylene groups, is at least 900, and z has a value such that the oxyethylene groups constitute about 10-90% of the total weight of the com pound.

4. A phosphating-cleaner composition consisting essentially of phosphate salt and organic detergent, said salt comprising about 90% by weight of said composition and said detergent comprising about 28% by weight of said composition and consisting of a conjugated polyoxypropylene-polyoxyethylene compound having the formula:

wherein Y is the residue of an organic compound containing therein x hydrogen atoms capable of reacting with 1,2-propylene oxide, x is an integer greater than one, y has a value such that the molecular weight of the compound, exclusive of the oxyethylene groups, is at least 900, and z has a value such that the oxyethylene groups constitute about 10-90% of the total weight of the compound.

S. A phosphating-cleaner composition consisting of the following listed components at substantially the weight percentages indicated:

Component: Weight percent Monosodium orthophosphate 91.5 Sodium molybdate 1.0 Pine oil 3.0 Glycollic acid 1.0 Sodium dibutylnaphthalene sulfonate 0.5 Alkylaryl polyethoxyether 1.0

Conjugated polyoxypropylene-polyoxyethylene compound 2.0

wherein said conjugated polyoxypropylene-polyoxyethylene compound conforms to the formula Component: Weight percent Monosodium orthophosphate 92.0 Sodium molybdate 1.0 Pine oil 3.0 Glycollic acid (70%) 1.0 Alkylaryl polyethoxyether 1.0

Conjugated polyoxypropylene-polyoxyethylene compound 2.0

said conjugated polyoxypropylene-polyoxyethylene compound conforming to the formula wherein Y is the residue of an organic compound containing therein x hydrogen atoms capable of reacting with 1,2-propylene oxide, x is an integer greater than one, has a value such that the molecular weight of the compound, exclusive of the oxyethylene groups, is at least 900, and z has a value such that the oxyethylene groups constitute about 10-90% of the total weight of the compound.

References Cited in the file of this patent UNITED STATES PATENTS 2,403,426 Douty et a1. July 2, 1946 2,479,423 Snyder Aug. 16, 1949 2,502,441 Dodd et a1 Apr. 4, 1950 OTHER REFERENCES Pluronics, published by Wyandotte Chemical Corporation, Wyandotte, Michigan. 13 pages. 

1. IN PHOSPHATING-CLEANER COMPOSITIONS CONSISTING ESSENTIALLY OF PHOSPHATE SALT AND ORGANIC DETERGENT, THE IMPROVEMENT WHEREIN AT LEAST 50% BY WEIGHT OF SAID DETERGENT CONSISTS OF A CONJUGATED POLYOXYPROPYLENEPOLYOXYETHYLENE COMPOUND HAVING THE FORMULA 